Globe maybe reused one of their old numbers to your postpaid mobile.
If you are recieving from just one or two persons, Globe prefers blocking the number instead. But if you are recieving texts from numerous persons, you may request for a change of number via a Globe Store and Hotline provided that you have the proofs about too many spams.
Also, we prefer you send samples to globe to prevent this in the future. Please visit globe.com.ph/stopspam